I. Field of the Invention
The present invention relates to a system and methods generally aimed at surgery. More particularly, the present invention is directed at a system and related methods for performing surgical procedures and assessments involving the use of neurophysiology.
II. Description of Related Art
Neurophysiology monitoring has become an increasingly important adjunct to surgical procedures where neural tissue may be at risk. Spinal surgery, in particular, involves working close to delicate tissue in and surrounding the spine, which can be damaged in any number of different ways. For example, an exiting nerve root may be comprised if surgical instruments have to pass near or close to the nerve while accessing the surgical target site in the spine. A spinal nerve and/or exiting nerve root may also be compromised if a pedicle screw, used often to secure fixation of multiple vertebra relative to each other, breaches the cortical layer of the pedicle. Surgeries targeting the spine may also require the retraction of nerve and/or vascular tissue out of the operative corridor. While doing so is necessary, there is a possibility of damaging nerve tissue through over retraction and/or a decreased supply of blood reaching the tissue due to the impingement of the retractor against the vascular tissue. Various neurophysiological techniques have been attempted and developed to monitor delicate nerve tissue during surgery in attempts to reduce the risk inherent in spine surgery (and surgery in general). Because of the complex structure of the spine and nervous system no single monitoring technique has been developed that may adequately assess the risk to nervous tissue in all situations and complex techniques are often utilized in conjunction one or more other complex monitoring techniques. EMG monitoring, for example, may be used to detect the presence of nerve roots near a surgical instrument or a breach formed in a pedicle wall. EMG monitoring is not, however, very effective when cord monitoring is required.
When cord monitoring is required one of motor evoked potential (MEP) and somatosensory evoked potential (SSEP) monitoring is often chosen. While both MEP and SSEP monitoring can be quite effective, MEP monitors the ventral column of the spinal cord and SSEP monitors the dorsal column. Danger to nerve tissue that might then be detected using one these methods may be missed by the other, and vice versa. Thus it may be most effective to use both MEP and SSEP monitoring during the same procedure, while still potentially needing EMG monitoring as well.
EMG, MEP, and SSEP involve complex analysis and specially trained neurophysiologists are generally called upon to perform the monitoring. Even though performed by specialists, interpreting the complex waveforms in this fashion is nonetheless disadvantageously prone to human error and can be disadvantageously time consuming, adding to the duration of the operation and translating into increased health care costs. Even more costly is the fact that the neurophysiologist is required in addition to the actual surgeon performing the spinal operation. Putting the difficulties associated with human interpretation of EMG, MEP, and SSEP monitoring aside, combining such testing in the OR generally requires multiple products to accommodate t the differing requirements of each. This is disadvantageous when space is often as such a premium in the operating rooms of today. The present invention is directed at eliminating, or at least reducing the effects of, the above-described problems with the prior art.